1. Technical Field
The invention relates generally to semiconductors, and particularly to an accelerometer.
2. Description of Related Art
Conventionally, micro-machined accelerometers utilize a movable electrode for a motion sensing capacitor. The electrode is deflected toward or away from a stationary electrode in response to acceleration.
The measured capacitance between the movable electrode and the stationary electrode is dependent upon numerous factors including the distance between the movable electrode and the stationary electrode. The sensitivity of the conventional micro-machined accelerometer is also dependent upon the area of the movable electrode that overlaps the stationary electrode and further upon the magnitude of the measured capacitance. Increase in the measured capacitance can increase the sensitivity of the conventional accelerometer, but requires an increase in the distance between the movable electrode and the stationary electrode, with corresponding increase in the volume of the accelerometer. Accordingly, sensitivity of the conventional accelerometer is limited by the volume of the accelerometer.
What is needed, therefore, is a micro-machined accelerometer with reduced sensitivity to the distance between the movable electrode and the stationary electrode.